Combine hydraulic valve

ABSTRACT

A control valve consisting of two-way normally closed solenoid poppet valves and two stage normally open solenoid poppet valves. The normally closed solenoid valves are arranged to direct flow to and from a cylinder in the desired manner. For the control of each single acting cylinder, one normally closed solenoid valve is required, whereas, for a double acting cylinder, four normally closed solenoid valves are needed. These sets of solenoid valves are incorporated in a single body or manifold to control the different functions on a combine such as reel height, reel speed, auger swing and traction drive. The control valve also includes a low flow circuit relief valve set at 2,000 psi and a 600 psi solenoid valve functioning as a relief valve to satisfy maximum pressure conditions for reel speed operation. The valve is located near to a supply pump and the pump flow passes through the normally open two-way solenoid valve and back to sump to minimize pressure drop in neutral.

United States Patent [191 Coleman COMBINE HYDRAULIC VALVE [75] Inventor:Martin W. Coleman, Independence,

[73] Assignee: Allis-Chalmers Corporation,

Milwaukee, Wis.

22 Filed: Jan. 22, 1973 21 Appl. No.: 325,957

[52] US. Cl 91/459, 91/414, 60/D1G. 2, 60/471 [51] Int. Cl. F151) 13/044[58] Field of Search 91/414, 459; 60/D1G. 2, 60/471 [56] ReferencesCited UNITED STATES PATENTS 2,318,851 5/1943 Griffith 60/97 P 2,425,39112/1947 Parsons 2,643,515 6/1953 Harsch 2,984,985 5/1961 MacMillin3,494,258 2/1970 Harms et al. 3,550,506 12/1970 Gardenhour 3,793,8312/1974 Khatti 91/414 REEL LIFT AUGER SWING [451 Oct. 22, 1974 PrimaryExaminerEdgar W. Geoghegan Assistant Examiner-William F. Woods Attorney,Agent, or Firm-Kenneth C. McKivett 5 7] ABSTRACT A control valveconsisting of two-way normally closed solenoid poppet valves and twostage normally open solenoid poppet valves. The normally closed solenoidvalves are arranged to direct flow to and from a cylinder in the desiredmanner. For the control of each sin gle acting cylinder, one normallyclosed solenoid valve is required, whereas, for a double actingcylinder, four normally closed solenoid valves are needed. These sets ofsolenoid valves are incorporated in a single body or manifold to controlthe different functions on a combine such as reel height, reel speed,auger swing and traction drive. The control valve also includes a lowflow circuit relief valve set at 2,000 psi and a 600 psi solenoid valvefunctioning as a relief valve to satisfy maximum pressure conditions forreel speed operation. The valve is located near to a supply pump and thepump flow passes through the normally open twoway solenoid valve andback to sump to minimize pressure drop in neutral.

2 Claims, 4 Drawing Figures TRACTION DRIVE REEL SPEED PMENIEDBUZZW AUGERSWING REEL LIFT Z TRACTION DRIVE72 REEL SPEED B131 7853? TO OPERATEENERGIZE VALVE SOLENOI DS RAISE 39 +4! REEL LIFT LOWER 4' UP 3e,a9+4-3AUGER SW'NG BACK aza9+42 FASTER 39+44 TRACTION DRIVE SLOWER v44 RAISE 3839 REEL SPEED LOWER 39 46 PAIENIEB 0m 2 2 I914 3.842.714 am at 'a WKwzao zoFu/ki mv w mm COMBINE HYDRAULIC VALVE CROSS REFERENCE TO RELATEDAPPLICATION This invention is an improvement over the combine controlshown in copendng US. application Ser. No. 260,741, filed June 8, 1972,now Pat. No. 3,793,831.

BACKGROUND OF THE INVENTION In a combine there are a number of poweroperated devices which must be controlled by an operator at a remoteoperators station. It has been found desirable to employ a hydrauliccontrol system in which some devices are controlled at a high pressurelevel and at least one device is controlled at a low pressure level. Inorder to increase the efficiency of the system, it has heretofore beenproposed to use an electric over hydraulic system (such as shown in US.Pat. No. 3,793,831) wherein a control manifold, with electricallyoperated solenoid valves, is placed near the pump and electric switchesfor controlling the electrically operated valves are placed in a consoleat the operators station. In such prior art control system, a separaterelief valve is placed in one branch circuit to establish a lowerpressure level for one control motor.

SUMMARY OF THE INVENTION The electric over hydraulic control system ofthis invention includes a hydraulic manifold having two pairs ofnormally closed solenoid valves controlling flow to a double actinghydraulic cylinder without the need of separate check valves. Anotherfeature of this invention is a combine control in which a single actinghydraulic cylinder is controlled by a pair of normally closed solenoidvalves one of which serves (1) as a relief valve when not energized and(2) as a dumping valve (to achieve a control function) when energized.

An object of this invention is to provide an improved electrohydrauliccontrol valve for controlling functions performed by single and doubleacting cylinders in an open center hydraulic system in a combineharvester.

Another object of this invention is to provide an inexpensiveelectrohydraulic control valve that will perform the functions ofthree-way and four-way spool valves with lockout check valves on mobileequipment.

Another object of this invention is to provide twoway solenoid valves inan open center hydraulic circuit to perform functions previouslyperformed by three and four-way spool valves with lockout check valves.

Another object of this invention is to provide a hydraulic systemwherein solenoid valves provide one or more functions at lower pressurethan system pressure.

A further object of this invention is to provide a hydraulic circuithaving a hydraulic cylinder and utilizing solenoid valves and in whicheach solenoid valve works as a directional control valve to controldirection of flow and as a check valve to a) isolate each function fromthe others in the circuit; and b) hold the hydraulic cylinder inactivated position.

BRIEF DESCRIPTION OF THE DRAWINGS Referring to the drawings:

FIG. 1 is a side elevation of a combine harvester embodying theinvention;

FIG. 2 is a schematic view of the invention;

FIG. 3 is a section view through the valve body partially shownschematically; and

FIG. 4 is a summary of functions provided by various combinations of thesolenoid valves.

DETAILED DESCRIPTION OF THE DRAWINGS Referring to FIG. 1, the inventionis embodied in a self-propelled combine harvester 10 having a main frame11 providing an operator station 12, a grain tank 13 provided with aswingable grain unloading auger 14, an internal combustion engine 15, anoperators control console 16 and a harvesting and threshing and cleaningmechanism 17 including a reel 18 mounted on the forward end of combine10. The foregoing are supported at the forward end of frame 11 ontraction wheels 19 which are operatively connected to engine 15 byconventional means (not shown). The rearward end of the combine 10 issupported on dirigible wheels 20 operatively connected to steering wheel21.

Mounted in the operators console 16 is a group of electrical switches22, 23, 24 and 26 (FIG. 2) which are positioned for easy manipulation bythe operator when positioned at station 12 (FIG. 1).

A valve body or hydraulic manifold 27 is positioned centrally on frame11 in reasonably close relation to pump 28, sump 29 and the functions ofthe combine to be hydraulically controlled. Pump 28 is operativelyconnected to engine 15 by conventional means (not shown). Valve body 27(FIG. 3) is provided with a main passage 31 connected at one end toconduit 32 to provide a passage between pump 28 and main passage 31. Aconventional relief valve 33 is interposed between conduit 32 andconduit 34 leading from sump 29 to pump 28.

Solenoid valves 36, 37, 38, 39, 41 and 42 are mounted in valve body 27in communication with main passage 31. Solenoid valves 43, 44 and 46 arealso mounted in valve body 27 in communication with main passage 31.Consider solenoid valve 36 which is a normally closed directacting'solenoid valve and normally open two stage solenoid valve 39 arearranged as shown in FIG. 3. For the present discussion, consider thatonly these two valves are installed in the valve body 27 and the othervalves are not present in FIG. 3.

Pump 28 is connected to the valve inlet port 47 of main passage 31. Thepump flow with none of the switches 22-26 (FIG. 2) actuated is asfollows: the flow (FIG. 3) goes through passages 31, 48, 49, 51 and line52 to the sump 29. Plunger 53 in solenoid valve 41 seats tight on theseat 54 and blocks the passage of flow from a motor or cylinder 56 to amotor passage or cavity 57. Valve 41 serves as a lock or check valve tohold cylinder pressure constant and also serves as a directional controlvalve to direct flow from cylinder 56 to cavity 57.

To extend reel lift cylinder 56, solenoid valves 39 and I 41 areenergized by pushing switch 22 upwardly. When coil 58 (FIG. 3) ofsolenoid valve 39 is energized, plunger 59 thereof moves and seats onpoppet 61 which in turn moves together with plunger 59 and seats onvalve seat 62 blocking flow between passages 48 and 49. The flow frompump 28 is now blocked from sump 29 and is available for any of thefunctions comprehended by the valves in valve body 27. The energizationof coil 63 of valve 41 causes plunger 53 to move away from seat 54allowing hydraulic fluid to flow from passage 47 to cavity 57. When thepressure in cavity 57 exceeds the pressure in cylinder 56, the pump flowpasses through passage 67, 68 and orifice 69 to cylinder 56. Orifice 69controls the rate at which the piston of cylinder 56 extends orretracts. Excess flow, when orifree 69 is controlling the rate at whichthe piston of cylinder 56 extends, goes over the relief valve 33.

De-energizing coil 63 will remove holding force from plunger 53 andspring 71 will force plunger 53 to position itself on seat 54 blockingpassage 67 to passage 57. When coil 58 of solenoid valve 39 isde-energized, plunger 59 will move away from poppet 61 which moves awayfrom seat 62 allowing the flow from pump 28 to go to sump 29. This putsvalve 39 back into neutral position. In this neutral position, reel liftcylinder 56 goes into hold position and the spring 71 holds the plunger53 on seat 54 of solenoid valve 41 which acts as a lock valve.

To retract cylinder 56, solenoid valve coil 63 of solenoid valve 41 isenergized by depressing switch 22 (FIG. 2) resulting in plunger 53 (FIG.3) being pulled away from seat 54 against spring 71. Plunger 53 movesaway from seat 54 allowing hydraulic fluid from cylinder 56 to go tocavity 57. Oil flows from cavity 57 through passages 31, 48, 49 and S1and line 52 back to sump 29. As soon as coil 63 of solenoid valve 41 isdeenergized, spring 71 forces plunger 53 on seat 54 blocking flow fromcylinder 56 to cavity 57.

The steps described above illustrate complete operation of the reel liftsection of the valve. The valve also has a traction drive section and areel speed section which are identical to the reel lift operation and arepeat of describing such operation is not deemed necessary exceptingthat the reel speed function is carried on at 600 psi maximum pressurewhereas the other functions, including the reel lift and traction drive,are at 2,000 psi. In the reel speed control operation, solenoid valves38 and 46 are arranged as shown in FIG. 3. Operation of this valvesection is identical to the operation of the reel lift cylinder sectionin that when solenoids 38 and 39 are energized to extend the reel speedcylinder 72, hydraulic fluid flows from pump 28 through valve 38, cavity73 and line 74 to cylinder 72. Pressure in cavity 73 is sensed bysolenoid valve 46 functioning as a relief valve and which regulates thepressure in cavity 73 at 600 psi. However, this does not affect thesystem pressure which is regulated by a relief valve 33 at 2,000 psi.During operation of functions other than reel speed, solenoid valve 38isolates cavity 73 from passage 31. If the pressure in cavity 73 exceeds600 psi, plunger 75 retracts against spring 76 permitting flow of fluidto sump 29 maintaining pressure of 600 psi in cavity 73. v

The auger swing section has a double acting cylinder 77 and operation ofthe auger swing is accomplished by solenoid valves 36, 37, 42 and 43.

Energizing solenoid valves 39, 36 and 43 will cause hydraulic fluid toflow through valve 36 to the auger swing cylinder piston end 78. Fluidfrom rod end 79 of the cylinder 77 will flow through valve 43 back tosump 29 and the cylinder 77 will extend. As soon as solenoid valves 39,36 and 43 are de-energized, cylinder 77 will go into hold position andbe held by solenoid valves, 36, 37, 42, and 43.

When solenoid valves 39, 37 and 42 are energized,

hydraulic fluid moves from pump 28 through valve 37 to the auger swingcylinder rod end 79. Hydraulic fluid from the base end 78 goes to thesump 29 through solenoid valve 42 and cylinder 77 retracts. Cylinder 77goes into the previously described hold position as soon as the solenoidvalves are de-energized.

Similar sections as described above, could be added to valve body 27 byinserting'additional sets of valves arranged in the same way as theauger swing section.

FIG. 3 shows the valve body 27 connected in an open center system. Pump28 supplies hydraulic fluid into valve body 27 at inlet port 47 and suchhydraulic fluid flows through passages 31, 48, 49, 51 and line 52 backto sump 29. Whenever normally open valve 39 is energized, pump flow isblocked from returning to sump 29 and pressure fluid becomes availableto all sections of valve body 27. Solenoid valves 41, 36, 37, 42 and 44act as check valves and they isolate each section from the other. Any ofthe functions available in the valve housing 27 can be operated aspreviously described without affecting the rest of the functions.

In neutral, solenoid valves 41, 42, 37 and 38 act as lock valves andhold the pressures in the respective cylinders. When these solenoidvalves are energized, they act'as directional control valves and directflow from the pump to the cylinder or vice-versa. Thus, both thefunctions of lock or check valve and that of directional control valveare accomplished by the unique arrangement shown in FIG. 3. Solenoidvalve 44 forms the traction drive section and this section functionsexactly as the reel lift section was described as functioning; namely:to extend traction drive cylinder 81, solenoid valve 44 is energized byraising switch 24 (FIG. 2); When coil 58 (FIG. 3) of solenoid valve 39is energized, plunger 59 moves and seats on poppet 61 which in turnmoves together with plunger 59 and seats on valve seat 62 closing thepassage between 48 and 49. The flow of pump 28 is now blocked from thesump 29 and is available for any of the functions in the valve. Whencoil 82 of the solenoid valve 44 is energized, plunger 83 moves awayfrom seat 84 allowing hydraulic fluid to flow from passage 31 throughpassage 86 to cavity 87. When pressure in cavity 87 exceeds cylinderpressure, such pressure fluid passes through passages 86, 87 and orifice88 to cylinder 81. Orifice 88 controls the rate at which cylinder 81extends or retracts. Excess flow, when orifice 88 is controlling therate at which cylinder 81 extends, goes over relief valve 33.

De-energizing coil 82 will remove the holding force from plunger 83against the bias of spring 85 and spring 85 will force the plunger 83 toposition on seat 84 blocking the passage from 86 to 87. When coil 58 ofsolenoid valve 39 is de-energized, plunger 59 will move away from poppet61 which moves away from seat 62 allowing pump flow to go to sump 29.This puts the valve back into neutral position. In neutral, tractiondrive cylinder 81 goes into hold position and is held on poppet seat 84of solenoid valve 44 which acts as a lock valve.

To retract cylinder 81, solenoid coil 82 is energized which pullsplunger 83 away from seat 84 against spring 85. Plunger 83 moves awayfrom seat 84 allowing hydraulic fluid from cylinder 81 to go to cavity87. I-Iydraulic fluid flows from cavity 87 through passages 86,

31, 48, 49, 51 and line 52 back to sump 29. As soon as coil 82 ofsolenoid valve 44 is de-energized, spring 85 forces plunger 83 on toseat 84 blocking flow from cylinder 81 to cavity 87 and valve 39 goesinto neutral.

Referring to FIG. 2, each of the switches 22, 23, 24 and 26 are shown tobe of a double throw type. Each switch is provided with an upperconnection 91 and a lower connection 92 leading to electrical powersource 93 on combine 10. Switch 22 is provided with a lower lead 94connected to the coil 63 of solenoid 41 so that by depressing switch 22coil 63 is energized. Switches 22, 23, 24 and 26 are also provided withan upper contact 96 which is connected to the coil 58 of solenoid 39.Switch 22 is also provided with an upper lead 97 connected to the coil63 of solenoid 41 so that by moving switch 22 upwardly power is suppliedto lines 96 and 97 for energizing solenoids 39 and 41.

Switch 23 is provided with a lower contact 98 connected to the coil ofsolenoid 42 and the coil of solenoid 37 and switch 23 is also provided alower contact 99 connected to contact 96 so that when switch 23 isdepressed solenoids 37, 39 and 42 are actuated for connecting the rodend 79 of cylinder 77 with line 31 and a source of hydraulic fluid andthe piston end 78 of cylinder 77 is connected up with sump 29,respectively. Switch 23 is also provided with an upper contact 101connected to the coils of solenoid valves 36 and 43 so that when switch23 is raised valves 36, 39 and 42 are actuated, the rod end 79 ofcylinder 77 is connected to sump 29 and the piston end 78 is connectedto line 31 for receiving hydraulic fluid from pump 28.

Switch 24 is provided with lower contact 102 connected to the coil ofsolenoid valve 44 so that when switch 24 is depressed solenoid 44 isenergized connecting cylinder 81 with line 31 for return to sump 29.Switch 24 is also provided with an upper contact 103 so that when switch24 is raised solenoids 39 and 44 are energized and hydraulic fluid flowsfrom pump 28 to cylinder 81 extending same.

Switch 26 is provided with lower contact 104 connected to the coil ofsolenoid valve 46 so that when switch 26 is depressed solenoid 46 isactuated to connect cylinder 72 with sump 29. Switch 26 is also providedwith an upper contact 106 so that when switch 26 is raised solenoids 39and 38 are energized and hydraulic fluid flows from pump 28 to cylinder72 extending same.

The engine on a combine must so run as to maintain constant speed on thethreshing and separating mechanisms. The ground speed, however, must bevariable in minute increments as crop conditions vary. This speedvariation is accomplished by a three-speed transmission driven through avariable diameter sheave arrangement. The effective diameter of thedriven sheave is increased by a single acting hydraulic cylinder 81 anddecreased by a spring in a conventional manner (not shown). To increasethe combine speed, an electrical signal is sent from operators station12 to solenoid members 39 and 44 by raising switch 24. When solenoidmember 39 closes it causes the normally open poppet 61 to close blockingthe flow through valve 39. When this happens pressure builds up in thevalve to approximately 2000 psi when relief valve 33 upstream relieves.Because solenoid 44 is also energized, it opens allowing hydraulic fluidto flow through orifice 88 to the traction drive cylinder 81. When theelectrical signal from switch 24 is taken away, solenoid 44 closestrapping the hydraulic fluid in the traction drive cylinder 81 andmaintaining that position of the variable diameter sheave arrangementand consequently, the speed of the vehicle. With no electrical signal,solenoid member 39 reopens and the hydraulic fluid is again free tocirculate past solenoid 39 and deposit in sump 29. To slow down thetraction speed, an electrical signal is sent to solenoid 44 bydepressing switch 24 at the operators station 12, this causes an openingof solenoid valve 44 and allowing the spring load to force the hydraulicfluid out of cylinder 81 through valve 44 and through valve 39 where itmoves to sump 29.

The reel height on the combine is maintained by a master-slavearrangement with only the master cylinder 56 being shown (FIG. 2). Toraise the reel 18 solenoid members 39 and 41 are energized by pressingup on switch 22. This allows hydraulic fluid exerting a 2000 psipressure to move past solenoid 41 to the reel lift cylinder 56. The reel18 (P10. 1) is held in its desired position by solenoid 41 reclosingwhen the electrical signal is removed. When it is desired to lower reel18 an electrical signal is transmitted to solenoid 41 by depressingswitch 22 at the operators station. This results in the opening ofsolenoid 41 and permitting hydraulic fluid in ram 56 to exit throughsolenoid 41 into line 31 and through solenoid 39 to sump 29.

The unloading auger 14 is moved into operative bin unloading position bya double acting cylinder 77. To swing auger 14 into such unloadingposition switch 23 is actuated upwardly at the operators station 12.This energizes solenoids 36, 39 and 43. The closing of solenoid 39causes a pressure build-up in line 31 which causes hydraulic fluid tomove through now open solenoid 36 to extend hydraulic cylinder 77.Hydraulic fluid from rod end 79 of cylinder 77 passes through now opensolenoid valve 43 to be deposited in sump 29. When auger 14 has beenswung to its operating position, it can be maintained in this positionby interrupting the electrical signal from switch 23. Such interruptioncauses solenoid 39 to move to an open position connecting line 31 withsump 29 and causes solenoids 36 and 43 to move to closed positionstrapping the hydraulic fluid in both ends of cylinder 77. When it isdesired to return auger 14 to its transport position alongside combine10, switch 23 is depressed actuating solenoids 37, 39 and 42. Theclosing of solenoid 39 causes a pressure build-up in line 31 whichcauses hydraulic fluid to move through now open solenoid 37 to retracthydraulic cylinder 77. Hydraulic fluid from piston end 78 of cylinder 77passes through now open solenoid valve 42 to be deposited in sump 29.When auger 14 has been swung to its transport position, it can bemaintained in this position by interrupting the electrical signal fromswitch 23. Such interruption causes solenoid 39 to move to an openposition connecting line 31 with sump 29 and causes solenoids 37 and 42to move to closed positions trapping the hydraulic fluid in both ends ofcylinder 77.

The speed of reel 18 is controlled by a conventional variable diametersheave drive (not shown) which by its design is limited to 600 psi. Thisdrive provides very little return force. This requirement has been metby the addition of a solenoid 46 which acts as a relief valve andunloading device. The poppet load orifice size relationship is such thatthe poppet will unseat and act as a direct acting relief valve at 600psi. To increase the reel speed solenoids 38 and 39 are energized bypressing up on switch 26. The closing of solenoid 39 results in abuild-up of pressure in line 31 which pressurefluid pressurizes reelspeed cylinder 72. This pressure is relieved to 600 psi by solenoid 46.To slow the reel down, solenoids 39 and 46 are energized. Solenoid 39closes stopping the flow of hydraulic fluid to sump 29. The magneticload at solenoid 46 unseats the 600 psi relief and allows the reel speedreturn hydraulic fluid to flow through an empty line 107 to sump 29.This allows the system to operate at 600 psi with very low returnpressures. The closing of solenoid valve 39 prevents dumping of fluidfrom the main passage 31 to sump by way of the common sump returnpassage, shown schematically in FIG. 2, thus allowing a low fluid returnpressure for reel speed motor 72; however, it is of course possible toexhaust fluid from motor 72 by opening solenoid valve 46 without closingvalve 39.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

1. In combination in a self-propelled combine harvester having a controlconsole positioned at an operators station, said combine being providedwith a hydraulic system including a pump and a sump, the improvementcomprising:

a double acting hydraulic cylinder,

a hydraulic manifold having a main passage connected in fluid receivingrelation to said pump and in fluiddelivery relation to said sump andhaving a pair of supply passages operatively connecting opposite ends ofsaid cylinder to said main passage, said manifold being positioned inremote relation to said console and proximate to said pump and sump toprovide a minimum'passage of hydraulic fluid between said pump and sumpwhen said hydraulic cylinder is not being operated,

a normally open solenoid valve mounted on said manifold and connected tosaid main passage, said normally open solenoid valve having an openposition permitting hydraulic fluid to pass from said main passage tosaid sump and a closed position blocking fluid from flowing from saidmain passage to said sump,

a first pair of normally closed solenoid valves mounted on said manifoldand connected respectively in controlling relation to said supplypassages, said first pair of normally closed solenoid valves openingwhen energized to permit fluid flow in said supply passages,respectively, between said main passage to said cylinder, said firstpair of normally closed solenoid valves being operative when notenergized to prevent flow of fluid through said supply passages fromsaid cylinder to said main passage,

a second pair of normally closed solenoid valves connected respectivelyto said supply passages and operable to control flow of fluid therefromto said sump, said second pair of normally closed solenoid valves whenopened being operative to pass fluid from said cylinder to said sumpwithout it passing through said main passage, and

a plurality of switches positioned in said control console forcontrolling said solenoid valves and so connected to the latter wherebyupon closing of selected switches on said console said normally opensolenoid valve will be closed permitting buildup of hydraulic pressurein said main passage and upon subsequently opening one of said firstpair of normally closed solenoid valves associated with one of saidsupply passages and opening the one of said second pair of normallyclosed solenoid valves associated with the other of said supplypassages, fluid is delivered to one end of said cylinder and exhaustedfrom the other.

2. In combination in a self-propelled combine harvester having a controlconsole positioned at an operators station, said combine being providedwith a hydraulic system including a pump, a sump and a plurality ofhydraulically operated devices including a hydraulic motor, theimprovement comprising:

a hydraulic manifold having a main passage connected in fluid receivingrelation to said pump and in fluid delivery relation to said sump and amotor passage connected at one endto said main passage and having itsother end connected to said motor,

a normally open solenoid valve mounted on said manifold connected incontrolling relation to said main passage, said normally open solenoidvalve having an open position permitting hydraulic fluid to pass fromsaid pump to said sump by way of said main passage and a closed positionblocking fluid from flowing from said pump to said sump by way of saidmain passage,

a first normally closed solenoid valve mounted on said manifold andconnected in controlling relation to said motor passage, said firstnormally closed solenoid valve functioning when not energized as a checkvalve preventing return flow from said motor through said motor passageand opening when energized to permit fluid flow in said motor passagebetween said main passage and said motor,

a first relief valve operatively connected to the output side of saidpump to establish a relatively high operating pressure for said mainpassage of said manifold when said normally open solenoid valve isclosed, second normally closed solenoid valve interconnected betweensaid motor passage and said sump and including a spring biased valveplunger operating as a second relief valve when said second valve is notenergized, said second valve establishing a lower operating pressure forsaid motor passage than that established for said main passage by saidfirst relief valve, and

a plurality of switches positioned in said control console forcontrolling said solenoid valves and connected to the latter wherebyupon closing of selected switches on said console said first normallyopen solenoid valve will be closed permitting buildup of hydraulicpressure in said main passage and upon subsequently opening saidnormally closed solenoid valve pressurized hydraulic fluid is suppliedthrough said normally closed solenoid valve and said motor passage tosaid one hydraulic motor causing said motor to be operated in onedirection, and fluid being permitted to flow to sump from said motor byway of said motor passage without passing through said main passage whena selected switch in said control console is operated to energize saidsecond normally closed solenoid valve thereby causing the latter toopen.

1. In combination in a self-propelled combine harvester having a controlconsole positioned at an operator''s station, said combine beingprovided with a hydraulic system including a pump and a sump, theimprovement comprising: a double acting hydraulic cylinder, a hydraulicmanifold having a main passage connected in fluid receiving relation tosaid pump and in fluid delivery relation to said sump and having a pairof supply passages operatively connecting opposite ends of said cylinderto said main passage, said manifold being positioned in remote relationto said console and proximate to said pump and sump to provide a minimumpassage of hydraulic fluid between said pump and sump when saidhydraulic cylinder is not being operated, a normally open solenoid valvemounted on said manifold and connected to said main passage, saidnormally open solenoid valve having An open position permittinghydraulic fluid to pass from said main passage to said sump and a closedposition blocking fluid from flowing from said main passage to saidsump, a first pair of normally closed solenoid valves mounted on saidmanifold and connected respectively in controlling relation to saidsupply passages, said first pair of normally closed solenoid valvesopening when energized to permit fluid flow in said supply passages,respectively, between said main passage to said cylinder, said firstpair of normally closed solenoid valves being operative when notenergized to prevent flow of fluid through said supply passages fromsaid cylinder to said main passage, a second pair of normally closedsolenoid valves connected respectively to said supply passages andoperable to control flow of fluid therefrom to said sump, said secondpair of normally closed solenoid valves when opened being operative topass fluid from said cylinder to said sump without it passing throughsaid main passage, and a plurality of switches positioned in saidcontrol console for controlling said solenoid valves and so connected tothe latter whereby upon closing of selected switches on said consolesaid normally open solenoid valve will be closed permitting buildup ofhydraulic pressure in said main passage and upon subsequently openingone of said first pair of normally closed solenoid valves associatedwith one of said supply passages and opening the one of said second pairof normally closed solenoid valves associated with the other of saidsupply passages, fluid is delivered to one end of said cylinder andexhausted from the other.
 2. In combination in a self-propelled combineharvester having a control console positioned at an operator''s station,said combine being provided with a hydraulic system including a pump, asump and a plurality of hydraulically operated devices including ahydraulic motor, the improvement comprising: a hydraulic manifold havinga main passage connected in fluid receiving relation to said pump and influid delivery relation to said sump and a motor passage connected atone end to said main passage and having its other end connected to saidmotor, a normally open solenoid valve mounted on said manifold connectedin controlling relation to said main passage, said normally opensolenoid valve having an open position permitting hydraulic fluid topass from said pump to said sump by way of said main passage and aclosed position blocking fluid from flowing from said pump to said sumpby way of said main passage, a first normally closed solenoid valvemounted on said manifold and connected in controlling relation to saidmotor passage, said first normally closed solenoid valve functioningwhen not energized as a check valve preventing return flow from saidmotor through said motor passage and opening when energized to permitfluid flow in said motor passage between said main passage and saidmotor, a first relief valve operatively connected to the output side ofsaid pump to establish a relatively high operating pressure for saidmain passage of said manifold when said normally open solenoid valve isclosed, a second normally closed solenoid valve interconnected betweensaid motor passage and said sump and including a spring biased valveplunger operating as a second relief valve when said second valve is notenergized, said second valve establishing a lower operating pressure forsaid motor passage than that established for said main passage by saidfirst relief valve, and a plurality of switches positioned in saidcontrol console for controlling said solenoid valves and connected tothe latter whereby upon closing of selected switches on said consolesaid first normally open solenoid valve will be closed permittingbuildup of hydraulic pressure in said main passage and upon subsequentlyopening said normally closed solenoid valve pressurized hydraulic fluidis supplied through said normally closed solenoiD valve and said motorpassage to said one hydraulic motor causing said motor to be operated inone direction, and fluid being permitted to flow to sump from said motorby way of said motor passage without passing through said main passagewhen a selected switch in said control console is operated to energizesaid second normally closed solenoid valve thereby causing the latter toopen.